I don't consider it a serious problem, as it is the same as undercolor in wheatens. I would be more concerned with the black hackle striping, and the shortage of orange color in the wing bay. If you can get all-black ( or blue in blue wheatens) muffs, that's great. I have seen them, usually in bantams with an all black wing bay. But I have always felt there were more important flaws to work on. It's just another reason why it is so much easier to win with an all black or all white bird.